public class Student3 extends Person3{
    private String stu_id;
    public Student3(String name,int age,genderEnum sex,String stu_id){
        super(name,age,sex);
        this.stu_id=stu_id;
    }

    public String getStu_id() {
        return stu_id;
    }

    public void setStu_id(String stu_id) {
        this.stu_id = stu_id;
    }
    public void study(){
//        if(person3 instanceof Student3){
////            Student3 student3=(Student3)person3;
//            System.out.println(person3.getName()+"爱玩足球");
//        }
        System.out.println(this.getName()+"会好好学习");

    }
}
